Escherichia coli
Microbiology · Molecular Biology
Say it: esh-uh-RIK-ee-uh KOH-ly
Escherichia coli is a rod-shaped, gram-negative gut bacterium that is mostly harmless but includes strains that cause diarrhea and urinary infections.
Also: E. coli
Definition
What is escherichia coli?
Escherichia coli is a rod-shaped, gram-negative bacterium that lives in the lower intestine of humans and other warm-blooded animals. It is a facultative anaerobe, able to grow with or without oxygen, and it ferments lactose, a trait used to pick it out on media such as MacConkey agar. Theodor Escherich described it in 1885. Most strains are harmless members of the gut microbiota that help their host, for example by making vitamin K and crowding out pathogens. Because it is shed in feces, finding E. coli in water or food signals fecal contamination.
Some strains carry extra genes, often gained by horizontal gene transfer, that make them pathogens. Six groups that cause diarrhea are recognized. Enterotoxigenic E. coli is a common cause of travelers' diarrhea, and Shiga toxin-producing strains such as O157:H7, spread by undercooked beef, raw produce and contaminated water, can lead to hemolytic uremic syndrome, a dangerous form of kidney failure. Other strains are the main cause of urinary tract infections and can cause sepsis and newborn meningitis.
E. coli is also the workhorse of molecular biology. It can divide every 20 minutes in rich medium, and harmless laboratory strains such as K-12 are used to clone genes and make proteins like human insulin.
Word parts
Where does the term “escherichia coli” come from?
- coli
- of the colonLatin, from Greek kolon
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Related
Terms that go with it
- Gram-negative bacteriaGram-negative bacteria have a thin peptidoglycan wall wrapped in an outer membrane, so they lose the purple dye in a Gram stain and look pink.
- MicrobiomeA microbiome is the community of bacteria, fungi, viruses and other microbes, with their genes, that lives in a particular place, such as the human gut.
- BacteriumA bacterium is a single-celled prokaryote with no nucleus, found in almost every habitat on Earth, including in and on the human body.
- PlasmidA plasmid is a small, usually circular DNA molecule that copies itself independently of the main chromosome, found mostly in bacteria.
- Molecular cloningMolecular cloning is a set of laboratory methods for inserting a specific DNA fragment into a vector and copying it many times inside host cells.
- PathogenA pathogen is a microbe or other agent, such as a virus, bacterium, fungus, parasite or prion, that can cause disease in a host.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- CDC: About Escherichia coli Infection
- OpenStax Microbiology, 24.3 Bacterial Infections of the Gastrointestinal Tract
- OpenStax Microbiology, 9.1 How Microbes Grow
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